Add NA transmit generate function for ND offload am: f545f33044

Original change: https://android-review.googlesource.com/c/platform/packages/modules/NetworkStack/+/3115588

Change-Id: I3cea1b7e1a1120ca2a33d6c33dbc41a6ea998a85
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>